Light-switchable gene expression system

Abstract

Provided is a light-switchable gene expression system, comprising: a) a recombinant light-switchable transcription factor-encoding gene, said recombinant light-switchable transcription factor comprising a first polypeptide as the DNA bonding domain, a second polypeptide as the photosensitive domain, and a third polypeptide as the transcription regulatory domain; b) a target transcription unit comprising at least one reaction element recognized and bound by the first polypeptide, a promoter regulated by the third polypeptide and a nucleotide sequence to be transcribed. Also provided is an eukaryotic expression vector comprising said light-switchable gene expression system, and a method for regulating gene expression in a host cell by using the light-switchable gene expression system. Also provided is a reagent kit containing different elements of the light-switchable gene expression system. The light-switchable gene expression system has a quick, effective and powerful induction with little or no toxicity. It is safer than other inducers, and can spatiotemporally control gene expression.

What is claimed is: 
     
       1. A light-switchable gene expression system, comprising: a) a gene encoding a photosensitive recombinant light-switchable eukaryotic transcription factor, said recombinant light-switchable eukaryotic transcription factor is one protein including a first polypeptide as DNA-binding domain, a second polypeptide as light-switchable domain and a third polypeptide as transcriptional regulatory domain; b) a target transcription unit, including at least one reaction element recognized/bound by the first polypeptide, a promoter regulated by the third polypeptide and a nucleic acid sequence to be transcribed; wherein said second polypeptide is selected from LOV2 domain of  Neurospora crassa  VIVID, AsLOV2 domain of oat phytochrome gene 1 and AuLOV domain in Aureochrome1 of  Stramenopile algae Vaucheria frigida.    
     
     
       2. The light-switchable gene expression system according to  claim 1 , wherein said first polypeptide, second polypeptide and third polypeptide were linked each other operatively and/or wherein said reaction element, promoter and nucleic acid sequence to be transcribed were linked each other operatively. 
     
     
       3. The light-switchable gene expression system according to  claim 1 , wherein said first polypeptide is selected from helix-turn-helix DNA-binding domain, zinc finger motif or zinc cluster DNA-binding domain, leucine zipper DNA-binding domain, winged helix DNA-binding domain, winged helix-turn-helix DNA-binding domain, helix-loop-helix DNA-binding domain, high mobility family DNA-binding domain and B3 DNA-binding domain. 
     
     
       4. The light-switchable gene expression system according to  claim 3 , wherein said first polypeptide is selected from DNA binding domain of yeast Gal4 protein. 
     
     
       5. The light-switchable gene expression system according to  claim 1 , wherein said third polypeptide is selected from transcriptional activation domains rich in acidic amino acids, transcriptional activation domains rich in proline, transcriptional activation domains rich in serine/threonine and transcriptional activation domains rich in glutamine, and Kruppel-retated box transcriptional repression domain. 
     
     
       6. The light-switchable gene expression system according to  claim 5 , wherein the third polypeptide is selected from transcriptional activation domains of the herpes simplex virus VP16 particle protein, transcriptional activation domains of yeast Gal4 protein, transcriptional activation domains of NF-κB p65 subunit, transcriptional activation domains of yeast general control protein 4, and Kruppel-retated box transcriptional repression domain of the zinc finger 354A protein. 
     
     
       7. The light-switchable gene expression system according to  claim 1 , further comprising a fourth polypeptide, i.e., nuclear localization signal peptide, which can promote the transportation of the recombinant light-switchable transcription factor into the nucleus, said fourth polypeptide links with the first, the second and the third polypeptides directly or via a linker peptide. 
     
     
       8. The light-switchable gene expression system according to  claim 1 , further comprising a fifth polypeptide regulated by hormones, said fifth polypeptide links with the first, the second and the third polypeptides directly or via a linker peptide. 
     
     
       9. The light-switchable gene expression system according to  claim 1 , wherein said reaction element is a DNA motif which can be specifically recognized and bound by the first polypeptide. 
     
     
       10. The light-switchable gene expression system according to  claim 9 , wherein said reaction element is selected from Gal4 binding element. 
     
     
       11. The light-switchable gene expression system according to  claim 1 , wherein the promoter is selected from the adenovirus late promoter, cytomegalovirus (CMV) minimal promoter, yeast Gal1 gene promoter and SV40 promoter. 
     
     
       12. The light-switchable gene expression system according to  claim 1 , wherein said first polypeptide and said second polypeptide constitute a light-switchable DNA-binding protein.